Nearly all passenger vehicles produced in the United States utilize a so-called mini-tire as the spare tire for the vehicle. These tires are intended only for temporary emergency use and the mini-tire and its associated wheel are of reduced physical dimensions as compared to the standard tire and wheel assemblies designed for long term every day usage.
In the typical vehicle assembly plant, a tire and wheel assembly line is operated in conjunction with the vehicle assembly line to feed mounted and inflated tires to the vehicle assembly line so that the correct size and style of tire and wheel arrive at the wheel mounting station on the main assembly line at the same time the vehicle upon which they are to be mounted reaches that station. In this system, every fifth tire and wheel fed to the main assembly line will be a mini tire-wheel. Thus, the mini tire and wheel assemblies are integrated into the tire mounting and inflation line with standard size tires and wheels.
Experience has shown that, because of the dimensions of the mini-wheel and tire and the manner in which the uninflated tire is mounted upon the mini wheel, a substantial number of mini wheel-tire units arrive at the inflator with the tire off-center with respect to its wheel to the point where the inflator cannot successfully inflate the tire. On some tire-wheel lines, the success rate of inflating mini-spares was only about 40%.
The problem of non-concentric positioning of the mini tire upon its wheel arises primarily because of the fact that the axial width of the drop well of the mini wheel is not much larger than the combined axial thicknesses of the mini tire beads. During the final stage of the tire mounting process the amount the tire beads must be stretched to force them inwardly over the rim flange of the wheel will pull the already mounted portion of the beads inwardly from the bead seats into the drop well at that portion of the wheel opposite the as yet unmounted portions of the bead.
The relatively narrow drop well of the mini wheel frequently will acquire a tight enough grip on the bead portions of the mini tire forced into the drop well during the mounting operation that it will hold the mounted mini tire in an off center relationship to the wheel through its arrival at the inflator. Typically, the wheel is used to align the wheel-tire assembly with the head of the inflator, and if the tire is not concentric with the wheel inflation cannot be accomplished. Unlike the standard tire-wheel assembly, the mini tire-wheel assembly is not subjected to a rotative wheel-to-tire orientation at a station between the mounter and inflator, hence the mini tire will normally maintain the same relationship with its wheel as exists as the unit leaves the mounter.
The present invention is especially directed to this problem and solves the problem by employing two relatively simple mechanisms operable upon the mini tire-wheel assembly at stations between the mounter and inflator to assure that the mini tire is centered with respect to its wheel as the unit reaches the inflator. The system of the present invention has inreased the percentage of inflated mini spare assemblies from the 40% figure referred to above to 99%.